Weather StoryAlmanac, microseasons, and the day's weather story.

Derby, Connecticut Weather

Cicadas claim the afternoon. Day 14 of summer. Read this microseason across nine climate regions →

Derby weather forecast — hour by hour, 7-day outlook, NOAA radar

Derby, CT
Saturday, July 4 at 8:11 AM
84
°
Clear
Feels like
88°
Humidity
64%
Wind
8 mph
Sunrise
1:24 AM
Sunset
4:28 PM
Derby, CT
Hour by hour · 24h
24-Hour ForecastDerby, CT: 24-hour forecast. Temperatures range from 72 to 98 degrees Fahrenheit with a 36% chance of precipitation at 8 PM.
L 72°H 98°
Derby, CT
7-day forecast
  1. Today
    Jul 4
    Drizzle
    36%
    0.03″
    98°75°—
  2. Sunday
    Jul 5
    Light Drizzle
    60%
    0.02″
    86°72°-12°
  3. Monday
    Jul 6
    Heavy Showers
    83%
    6.2″
    71°62°-15°
  4. Tuesday
    Jul 7
    Light Rain
    68%
    0.34″
    63°59°-8°
  5. Wednesday
    Jul 8
    Overcast
    —
    —
    81°54°+18°
  6. Thursday
    Jul 9
    Mostly Clear
    13%
    —
    84°63°+3°
  7. Friday
    Jul 10
    Light Drizzle
    34%
    —
    89°68°+5°
Derby, CT
Next 24 hours · Warm now
HOT 90°65°85°105°6a12p6p12anow 84°high 98°low 72°PRECIP %
Derby, CT
Anemometer · 24h winds · from true
NESW
From · True
WNW
292° · backing 8°
Direction
WNW
292°
Sustained
8
mph
Gust
15
mph
Peak 24h
21
avg 7
Beaufort · 3 · GENTLE BRZ
0
CALM
<1
1
LIGHT AIR
1–3
2
LIGHT BRZ
4–7
3
GENTLE BRZ
8–12
4
MOD BRZ
13–18
5
FRESH BRZ
19–24
6
STRONG BRZ
25–31
7
NEAR GALE
32–38
24h · sust vs gust · mph
avg 7 · pk 21 @ 11:00p
0102030MPHB1B2B3B4B5B6B7-21h-18h-15h-12h-9h-6h-3h-24hNOWpk 292SUSTGUST
−24h−18h−12h−6hnow
Light breeze backing 8° from the wnw.
Derby, CT
Barometer · 24h pressure · mb
STORMRAINCHANGEFAIRDRY9901000101010201030
Pressure · mb
1011.0
+0.1 mb in 3h · steady · 29.85 inHg
Now
1011.0
mb
3h
+0.1
mb
12h
+0.9
mb
24h
-2.6
mb
Regime · CHANGE
STORM
RAIN
CHANGE
FAIR
DRY
24h · Pressure · mb
range 1010–1014
9951000STORM|RAIN10051010RAIN|CHG1015CHG|FAIR10201025FAIR|DRY1030-21h-18h-15h-12h-9h-6h-3h-24hNOW1013.61009.91011.0
−24h−18h−12h−6hnow
Air sits at the threshold — small shifts decide the day.
Derby, CT
Air quality
34
AQI
Good
↓-6 in 6h▲Peak ~50 @ 6 PM

AQI 34 (Good), driven by PM2.5. AQI down 6 over the last 6 hours (gradual decline). PM2.5 at 8.6 µg/m³, PM10 at 9.4 µg/m³ — typical background levels with no transport signature.

OK No precautions needed for the general population; unusually sensitive individuals may consider limiting prolonged outdoor exertion during the projected peak around 6 PM.

PM 2.5DRIVERGood
8.6μg/m³
PM 10Good
9μg/m³
NO₂Good
3μg/m³
OzoneModerate
92μg/m³
UV IndexLow
1.6

What's driving it

Ozone × UV × Sky

Ozone at AQI 43 now. With UV 5.3 peaking around 1 PM under clear skies, surface ozone likely climbs to AQI 31 around 1 PM.

Present
AQI 43
UV peak
5.3 at 1 PM
Sky at peak
clear
Projected peak
AQI 31

PM × Wind × Precip

PM2.5 at 8.6 µg/m³, PM10 at 9.4 µg/m³ — typical background levels with no transport signature.

PM2.5/PM10
0.91
Wind
light
Recent rain
0h in last 6h
Pattern
background

Trends

Seven days of AQI and PM2.5.

Hourly air-quality data from the Copernicus Atmosphere Monitoring Service, charted across the past and next several days. Dashed lines mark the AQI breakpoints at 50 (Good → Moderate) and 100 (Moderate → Unhealthy for Sensitive Groups).

7-DAY AQI TREND50100SATSUNMONTUEWEDTHUFRISAT7-DAY PM2.5 TREND · μg/m³500
Derby, CT
Sky cover · visibility · 24h
Cloud cover
0%
CLEAR
100%0%−24h−18h−12h−6hnow
Visibility
52.8mi
UNLIMITED
111 mi0 mi−24h−18h−12h−6hnow
Earth · GOES-19 ABI
Full Disk · Visible · GeoColor
GOES-19 full disk Visible · GeoColor
True-color daytime, blue/IR sandwich at night
12:11 UTC · Derby, CT · NOAA NESDIS / STAR · up to 10848 px
Continental US · GOES-19 ABI
CONUS Sector · Visible · GeoColor
GOES-19 CONUS Visible · GeoColor
Daytime true-color, blue-light/IR sandwich at night
12:11 UTC · Derby, CT · NOAA NESDIS / STAR · 5-min cadence · up to 10000 px
Derby, CT
Satellite · infrared · animated
Derby, CT
Loading IR frames…
IR · cloud-top temp© RainViewer · Carto
Derby, CT
Almanac · Saturday, July 4
If the first of July be rainy weather, 'twill rain more or less for four weeks together.
Civil dawn
4:51 AM
Sunrise
1:24 AM
Daylight
15h 04m
Sunset
4:28 PM
Civil dusk
9:03 PM
Planting note
Harvest early potatoes. Begin drying onions on the surface.
Derby, CT
The moon
Waning Gibbous
82% illuminated
Moonrise
10:48 PM
Moonset
9:54 AM
In sign
♓︎ Pisces
Derby, CT
Microseason
Jul 1–5

Cicadas claim the afternoon

plant
Jan 151% of the yearDec 31

Read this microseason across nine climate regions →

Derby at a glance

  • Today vs. normal: 14°F above the seasonal normal for this latitude
  • Last frost: April 24 (climatological average for this latitude)
  • Microseason: Jul 1–5
  • Planting window: Harvest early potatoes. Begin drying onions on the surface.

ZIP code: 06418

16-Day Forecast — Derby

  1. Sat98°75°36%
  2. Sun86°72°60%
  3. Mon71°62°83%
  4. Tue63°59°68%
  5. Wed81°54°9%
  6. Thu84°63°13%
  7. Fri89°68°34%
  8. Sat75°69°23%
  9. Sun69°65°27%
  10. Mon68°62°20%
  11. Tue71°63°20%
  12. Wed81°60°26%
  13. Thu95°69°26%
  14. Fri95°71°36%
  15. Sat85°73°35%
  16. Sun89°67°40%

Forecast data from Open-Meteo (CC BY 4.0).

Right now in the garden

Peak growing season

As of July 4, the growing season is at its peak — frost is months away. Continue succession-planting beans and summer squash. Start fall brassicas (broccoli, cabbage, kale) from seed indoors for transplanting in late summer.

SPC Convective Outlook

Storm Prediction Center — Derby

SPC has placed Derby in the Marginal Risk category for severe thunderstorms today.

  • TODAYMRGLMarginal Risk
  • TOMORROWTSTMGeneral Thunderstorms
  • DAY 3TSTMGeneral Thunderstorms

Isolated severe storms possible. Limited threat for hail or damaging wind.

Source: NOAA / NWS Storm Prediction Center categorical convective outlook. Outlooks are re-issued multiple times per day; this page reflects the most recent SPC polygons covering the city’s coordinates.

January 1–5: The year turns in silence.January 6–10: Ice thickens on still water.January 11–15: Shortest shadows lengthen.January 16–20: Pheasants begin to call.January 21–25: Springs begin to thaw.January 26–31: Chickadees announce dawn.February 1–5: East wind softens the frost.February 6–10: Sap begins to rise.February 11–15: First snowdrops appear.February 16–20: Red-winged blackbirds return.February 21–25: Rain begins to replace snow.February 26–28: Skunk cabbage pushes through ice.March 1–5: Ice withdraws from the reservoir.March 6–10: Crocuses open to weak sun.March 11–15: Peepers call from the marsh.March 16–20: Woodcocks spiral at dusk.March 21–25: Equinox — light overtakes dark.March 26–31: Forsythia opens along the fences.April 1–5: Cherry blossoms drift like snow.April 6–10: Warblers appear in the understory.April 11–15: Magnolias bloom and fall in a day.April 16–20: Dogwoods float above the forest.April 21–25: Lilacs perfume the evening.April 26–30: Last frost releases the garden.May 1–5: Warblers flood the Ramble.May 6–10: Tulip poplars light their candles.May 11–15: Shad run up the rivers.May 16–20: Roses open along the stoops.May 21–25: Firefly scouts appear at dusk.May 26–31: Strawberries ripen in the sun.June 1–5: Fireflies rise from the lawn.June 6–10: Elderflowers open in hedgerows.June 11–15: Solstice approaches — longest light.June 16–20: Honeysuckle sweetens the night.June 21–25: Solstice — the sun stands still.June 26–30: Lightning bugs drift through oaks.July 1–5: Cicadas claim the afternoon.July 6–10: Queen Anne's lace lines the roads.July 11–15: Thunder builds each afternoon.July 16–20: Corn reaches for the tassels.July 21–25: Dog days settle in the haze.July 26–31: Katydids begin their chorus.August 1–5: Night falls a minute earlier.August 6–10: Sunflowers face the morning.August 11–15: Goldenrod begins to bloom.August 16–20: Crickets pulse through warm nights.August 21–25: First cool morning surprises.August 26–31: Monarchs stage for flight.September 1–5: School buses reappear.September 6–10: Asters purple the roadsides.September 11–15: Hawk migration over the Hudson.September 16–20: Equinox — dark overtakes light.September 21–25: Apples hang heavy on the branch.September 26–30: Geese begin to chevron south.October 1–5: Witch hazel blooms as others fade.October 6–10: Maples begin to blaze.October 11–15: Frost paints the garden black.October 16–20: Oaks turn bronze and russet.October 21–25: Leaves rattle down the gutters.October 26–31: Clocks fall back — dusk at five.November 1–5: Ginkgos drop overnight.November 6–10: Last leaves cling stubbornly.November 11–15: Juncos arrive from the north.November 16–20: Bare branches reveal the sky.November 21–25: First flurries dust the rooftops.November 26–30: Woodsmoke curls through the block.December 1–5: Darkness settles before dinner.December 6–10: Holly and winterberry persist.December 11–15: Shortest day approaches.December 16–20: Ice begins to form at the edges.December 21–25: Solstice — the sun begins return.December 26–31: The year turns in silence.🌱February 14 — First skunk-cabbage spathes thaw their way up☀️March 20 — Spring equinox — day and night balance🌸April 5 — Cherry blossoms peak in the parks🐦May 10 — Warbler migration peaks along the coast✨May 25 — First fireflies scout the meadows at dusk🌞June 21 — Summer solstice — longest day🦗July 25 — Peak cicada chorus in the afternoons🌊August 18 — Warmest sea-surface temperatures of the year🍂September 22 — Autumn equinox — the slow turn❄️October 25 — First widespread frost in the suburbs🍁November 10 — Peak leaf color across the Hudson Valley🌙December 21 — Winter solstice — longest night

Microseason · July 1–5

Cicadas claim the afternoon

Annual cicada buzz begins, peaking in the heat of the day.

Day 185 of 365 · Wedge 37 of 72

The solar year drawn as a wheel of 72 five-day windows. Each wedge is one microseason; the four colored arcs mark winter, spring, summer, and autumn; the small icons sit at notable phenological events. The crimson pointer creeps clockwise as the year turns.

Planting calendar

MonthPlantHarvest
January——
February——
March——
Aprillettuce, peas, spinach, radishes—
Maylettuce, peas, spinach, radishes, tomatoes, peppers, beans, squashlettuce, peas, radishes
Junetomatoes, peppers, beans, squashlettuce, peas, radishes
Julytomatoes, peppers, beans, squashtomatoes, beans, summer squash
August—tomatoes, beans, summer squash
Septemberfall brassicas, garlic (overwinter), carrotstomatoes, beans, summer squash
Octoberfall brassicas, garlic (overwinter), carrotswinter squash, tomatoes (last)
November——
December——

A year in weather

July is Derby's warmest stretch (~75°F) and January its coldest (~30°F); precipitation crests in December at 4.7 inches and ebbs in February to 3.3 inches.

MonthMean tempPrecipRainy days
January30°4.0″14
February32°3.3″14
March39°3.9″16
April50°4.3″18
May58°4.0″19
June68°3.9″18
July75°3.6″18
August74°4.0″17
September68°3.7″14
October58°3.7″13
November45°4.6″14
December35°4.7″14

Regional context

Per NOAA NCEI 1991-2020 normals, Derby runs from a 30°F January mean to 75°F in July, a 45°F seasonal spread, with near 47.7 inches of precipitation across about 188 wet days.

No season owns Derby's rain: December reaches 4.7 inches across 13.9 days and February keeps 3.3 inches on 13.5, an even spread through Derby's year. It is a balanced pattern Derby shares with places like Ansonia, CT, Shelton, CT and Oronoque, CT.

Around mid-April, Derby sheds its freezing nights — peas, lettuce, spinach, and radishes go into Derby's beds. Derby's heat-lovers — tomatoes, peppers, squash — hold off until Derby's frost risk clears, 10-14 days on. By mid-November, frost is back in Derby — protect or harvest anything tender. A creek-bottom lot in Derby can lag Derby's last frost 7-10 days behind a south slope.

Similar climates: Ansonia, CT, Shelton, CT, Oronoque, CT, East Village, CT, Daniels Farm, CT.

Frequently asked

When does it freeze in Derby?
Derby's last spring frost lands near mid-April, and in Derby the first fall frost follows around mid-November.
What is the rainy season in Derby?
Rainfall in Derby peaks in December near 4.7 inches, out of about 48 inches annually.
What is the warmest month in Derby?
On average July tops the year in Derby at about 75°F.
What is the coldest month in Derby?
The coldest stretch in Derby falls in January, around 30°F on average.
When can I start a vegetable garden in Derby?
In Derby, sow peas and hardy greens around mid-April; Derby's tomatoes and peppers wait two weeks more.
How many rainy days does Derby get?
Derby records around 188 days of measurable precipitation annually.
What hardiness zone is Derby?
With January around 30°F, Derby's zone reflects that minimum — the USDA ZIP map confirms Derby's band.
What is the 10-day forecast for Derby?
Derby's extended outlook — daily high and low temperatures and precipitation chances for each upcoming day — is in the daily forecast above.
Will it rain this week in Derby?
See this week's day-by-day rain chances for Derby in the daily forecast above, and the next 24 hours in the hourly chart.
What is the weather like right now in Derby?
Current conditions for Derby and the next 24 hours — temperature, precipitation chance, and wind by the hour — are in the hourly forecast chart above.
How often is the Derby forecast updated?
The Derby forecast on this page is built from Open-Meteo weather-model data and refreshes regularly through the day.
When are sunrise and sunset in Derby?
Today's sunrise and sunset times for Derby are in the Almanac section above, along with civil dawn, civil dusk, and day length. Day length is longest near the summer solstice and shortest near the winter solstice.
How accurate is the weather forecast for Derby?
The next few days in Derby's forecast are the most reliable; accuracy declines beyond about a week as weather-model uncertainty grows.

Climate

Set in a warm-summer humid continental zone, Derby, Connecticut swings from 30°F in the heart of winter to 75°F at midsummer — a 45°F arc.

Across the year, Derby collects about 48 inches of precipitation over roughly 188 days with measurable rain or snow.

Derby sits at 41.3°N; that 45°F seasonal swing frames planting windows and frost dates across Derby.

All cities in Connecticut →

New Haven, CT weather →

ZIP codes in Derby

  • 06418

Climate normals from the Open-Meteo Climate API. Köppen approximation from NOAA NCEI U.S. Climate Regions. See methodology for data sources, editorial rules, and corrections. Maintainer: Brian Tighe.